Nightlight base



FIG. 1 is a front perspective view of a nightlight base showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a left side elevational view thereof;

FIG. 5 is a rear elevational view thereof;

FIG. 6 is a bottom plan view thereof;

FIG. 7 is a right side elevational view thereof.

The light bulb is shown in broken lines for illustrative purposes only. 

The ornamental design for a nightlight base, as shown and described. 